1) Field of the Invention
This invention relates to personal transportation for pulling a user over a variety of base surfaces. More particularly the invention relates to a traction vehicle for pulling a user on in-line skates, skis or ice skates or the like through hand grips to transmit pulling forces to the user while permitting steering.
2) Prior Art
Other pulling vehicle systems are known in the art. Prior art known to Applicant as a result of prior examination and searches are U.S. Pat. Nos. 3,791,469; 5,540,296; 3,826,323; 2,369,936; 3,412,821; 3,419,095; 3,444,945; 2,645,297; 3,557,893; 3,380,546; 4,645,022; 5,090,714; 5,385,210; 4,456,089; 3,750,777; 3,797,448; 4,109,732; 3,826,323; 4,096,919; 3,777,835; 5,025,876; 3,635,301; 3,193,038; 4,418,776; 5,211,254; German Offenlegungsschrift 2,319,618; and Great Britain Patent Specification 991,730.
Of particular interest is U.S. Pat. No. 5,385,210 which pertains to a motorized device for pulling a user on inline skates. This vehicle consists of a single wheel with two batteries that sit fore and aft of a single wheel; in addition, two poles with handles extended outward for steering. Though the vehicle will assist a skater under ideal conditions, numerous problems will arise when the user or environment is altered. This is explained as follows:
A) Because the vehicle has only one central wheel and is balanced at the point of tire contact with the road, it is the user who must always maintain the balance of the vehicle.
Maintaining this balance could be an impossible task if the vehicle is traversing a sloped surface or if the user does not have sufficient body strength to overcome a vertical shifting of handle position, e.g., going down a hill.
B) While the object of a pulling or towing vehicle is to provide a means of forward movement, it should also provide the user a means of resistance (to move in opposition to), to assist the balance of the user. If the vehicle has a shifting center of momentum, as the single wheel vehicle does, then its ballast and resistance can not be relied upon in all instances to balance the user. If, for example, negotiating a turn on level ground, centripetal force causes the vehicle and user to become unbalanced in the same vector direction, the single wheeled vehicle will tip in the same direction as the user, thus further aggravating his/her imbalance.
C) Steering a single-wheeled vehicle is difficult because it assumes the user has sufficient strength, balance and control to oppose the forces needed to maneuver an object. Since the steering requires a sufficiently strong and balanced user, it follows that if the user is not balanced, the steering will be inaccurate.
D) The above liabilities are proportional to the weight of the vehicle. This becomes an added problem since the desired power and performance of electric vehicles are directly dependent upon battery capacity; batteries are usually the single heaviest component of an electric vehicle.
E) The pole handles or grips are affixed to the vehicle, which limit the user's freedom of movement--especially in the arms, shoulders and torso.
F) The poles need proper adjustment to fit the height of the user. It follows, therefore, that the poles go out of adjustment as the user bends and straightens his/her legs.
Simply stated, this design does not optimize control and maneuverability.
Another prior art vehicle system is found in U.S. Pat. No. 3,791,469 and is designed for skiers. This vehicle uses a gas-driven engine with a differential and four drive wheels. Using it along a city street or in the back-country will not be as "environmentally" pleasing as using an electric pulling vehicle. This art has only a single handle, which again restricts movement of the arms, shoulders and upper torso, nor does it allow the arms to move independently. Furthermore, steering is accomplished by only one means and that is by braking one wheel at a time through cable operated disc brakes. This method is not only inefficient and heavy, but the braking ability of a tire on a snow surface to turn a vehicle is not nearly as effective as the applicant's pulling vehicle which has three distinct methods of steering, and which all can be used simultaneously.
Other references uncovered include GB 991,730 in which a tiller-controlled vehicle is disclosed wherein movement of the tiller side-to-side affected steering.